Optical pickup

Abstract

Two types of objective lenses are arranged in a radial direction of an optical disc, a light flux reflecting/transmitting member arranged with first and third optical films for reflecting the beam light and a second optical film for reflecting or transmitting the beam light is arranged on the side opposite to the disc of the objective lenses. The beam light emitted from the laser diodes is entered to the light flux reflecting/transmitting member in a tangential direction of the disc. The beam light entering the light flux reflecting/transmitting member is reflected with the first optical film to be bent in the radial direction, and the BD beam light is reflected with the second optical film so as to enter to the BD objective lens, and the DVD/CD beam light is transmitted through the second optical film, and reflected with the third optical film so as to enter the DVD/CD objective lens.

1 . An optical pickup comprising:
 a light source for emitting a beam light corresponding to different types of optical discs;
 a first objective lens for collecting the beam light corresponding to one optical disc on the corresponding optical disc; and 
 a second objective lens for collecting the beam light corresponding to another optical disc on the corresponding optical disc, the optical pickup performing at least one of reproduction and recordation of information on each optical disc with the corresponding beam light, the optical pickup further comprising: 
 a light flux reflecting/transmitting member arranged with a first optical film and a third optical film for reflecting the beam light, and a second optical film for reflecting or transmitting the beam light, wherein 
 the first and second objective lenses are arranged in a radial direction of the optical disc, 
 the light flux reflecting/transmitting member is arranged on a side opposite to the optical disc of the first and second objective lenses, 
 the beam light emitted from the light source is entered to the light flux reflecting/transmitting member in a tangential direction of the optical disc, and 
 the light flux reflecting/transmitting member reflects the entered beam light with the first optical film to be bent in the radial direction of the optical disc, reflects one of the beam lights with the second optical film so as to make the beam light enter the first objective lens, transmits the other beam light through the second optical film and reflects the other beam light with the third optical film so as to make the other beam light enter the second objective lens. 
   
   
   
       2 . The optical pickup according to  claim 1 , wherein the light flux reflecting/transmitting member includes one compound prism integrally arranged with the first, the second, and the third optical films. 
   
   
       3 . The optical pickup according to  claim 1 , wherein the light flux reflecting/transmitting member includes one mirror integrally arranged with the first optical film and one compound prism integrally arranged with the second and the third optical films. 
   
   
       4 . The optical pickup according to  claim 1 , wherein the light flux reflecting/transmitting member includes three mirrors integrally arranged with the first, the second, and the third optical films, respectively. 
   
   
       5 . An optical pickup comprising:
 a light source for emitting a beam light corresponding to different types of optical discs;
 a first objective lens for collecting the beam light corresponding to one optical disc on the corresponding optical disc; and 
 a second objective lens for collecting the beam light corresponding to another optical disc on the corresponding optical disc, the optical pickup performing at least one of reproduction and recordation of information on each optical disc with the corresponding beam light, the optical pickup further comprising: 
 a light flux reflecting/transmitting member arranged with a first optical film and a third optical film for reflecting the beam light, and a second optical film for reflecting or transmitting the beam light, wherein 
 the first and second objective lenses are arranged in a radial direction of the optical disc, 
 the light flux reflecting/transmitting member is arranged on a side opposite to the optical disc of the first and second objective lenses, 
 the beam light emitted from the light source is entered to the light flux reflecting/transmitting member in a tangential direction of the optical disc, and 
 the light flux reflecting/transmitting member reflects the entered beam light with the first optical film to be bent in a thickness direction of the optical disc, transmits one of the beam lights through the second optical film so as to make the beam light enter the first objective lens, reflects the other beam light with the second optical film to be bent in the radial direction of the optical disc, and reflects the other beam light with the third optical film so as to make the other beam light enter the second objective lens. 
   
   
   
       6 . The optical pickup according to  claim 5 , wherein the light flux reflecting/transmitting member includes one mirror integrally arranged with the first optical film and one compound prism integrally arranged with the second and the third optical films. 
   
   
       7 . The optical pickup according to  claim 1 , wherein the second optical film of the light flux reflecting/transmitting member includes a wavelength selection film for selectively reflecting or transmitting each beam light according to its wavelength. 
   
   
       8 . The optical pickup according to  claim 7 , wherein the light source emits a first beam light having a first wavelength, a second beam light having a second wavelength longer than the first wavelength, and a third beam light having a third wavelength longer than the second wavelength, and the second optical film of the light flux reflecting/transmitting member reflects the first beam light and transmits the second and third beam lights. 
   
   
       9 . The optical pickup according to  claim 7 , wherein the light source emits a first beam light having a first wavelength, a second beam light having a second wavelength longer than the first wavelength, and a third beam light having a third wavelength longer than the second wavelength, and the second optical film of the light flux reflecting/transmitting member transmits the first beam light and reflects the second and third beam lights. 
   
   
       10 . An optical pickup comprising:
 a light source for emitting a first beam light corresponding to a BD, a second beam light corresponding to a DVD, and a third beam light corresponding to a CD;
 a first objective lens for collecting the first beam light on the BD; and 
 a second objective lens for collecting the second or the third beam light on the DVD or the CD, the optical pickup performing at least one of reproduction and recordation of information on each optical disc with the corresponding beam light, the optical pickup further comprising: 
 a light flux reflecting/transmitting member including one compound prism integrally arranged with a first optical film, a second optical film, and a third optical film, wherein 
 the first and third optical films include a total reflection film for reflecting the beam light, 
 the second optical film includes a dichroic film for selectively reflecting or transmitting the beam light according to its wavelength, 
 the first and second objective lenses are arranged in a radial direction of the optical disc, 
 the light flux reflecting/transmitting member is arranged on a side opposite to the optical disc of the first and second objective lenses, 
 the beam light emitted from the light source is entered to the light flux reflecting/transmitting member in a tangential direction of the optical disc, and 
 the light flux reflecting/transmitting member reflects the entered beam light with the first optical film to be bent in the radial direction of the optical disc, reflects the first beam light with the second optical film so as to make the first beam light enter the first objective lens, transmits the second or third beam light through the second optical film, and reflects the second or third beam light with the third optical film so as to make the second or third beam light enter the second objective lens. 
   
   
   
       11 . An optical pickup comprising:
 a light source for emitting a first beam light corresponding to a BD, a second beam light corresponding to a DVD, and a third beam light corresponding to a CD;
 a first objective lens for collecting the first beam light on the BD; and 
 a second objective lens for collecting the second or the third beam light on the DVD or the CD, the optical pickup performing at least one of reproduction and recordation of information on each optical disc with the corresponding beam light, the optical pickup further comprising: 
 a light flux reflecting/transmitting member including one mirror integrally arranged with a first optical film and one compound prism integrally arranged with a second optical film and a third optical film, wherein 
 the first and third optical films include a total reflection film for reflecting the beam light, 
 the second optical film includes a dichroic film for selectively reflecting or transmitting the beam light according to its wavelength, 
 the first and second objective lenses are arranged in a radial direction of the optical disc, 
 the light flux reflecting/transmitting member is arranged on a side opposite to the optical disc of the first and second objective lenses, 
 the beam light emitted from the light source is entered to the light flux reflecting/transmitting member in a tangential direction of the optical disc, and 
 the light flux reflecting/transmitting member reflects the entered beam light with the first optical film to be bent in a thickness direction of the optical disc, transmits the second or the third beam light with the second optical film so as to make the second or the third beam light enter the second objective lens, reflects the first beam light with the second optical film to be bent in the radial direction of the optical disc, and reflects the first beam light with the third optical film so as to make the first beam light enter the first objective lens. 
   
   
   
       12 . The optical pickup according to  claim 2 , wherein the second optical film of the light flux reflecting/transmitting member includes a wavelength selection film for selectively reflecting or transmitting each beam light according to its wavelength. 
   
   
       13 . The optical pickup according to  claim 3 , wherein the second optical film of the light flux reflecting/transmitting member includes a wavelength selection film for selectively reflecting or transmitting each beam light according to its wavelength. 
   
   
       14 . The optical pickup according to  claim 4 , wherein the second optical film of the light flux reflecting/transmitting member includes a wavelength selection film for selectively reflecting or transmitting each beam light according to its wavelength. 
   
   
       15 . The optical pickup according to  claim 5 , wherein the second optical film of the light flux reflecting/transmitting member includes a wavelength selection film for selectively reflecting or transmitting each beam light according to its wavelength. 
   
   
       16 . The optical pickup according to  claim 6 , wherein the second optical film of the light flux reflecting/transmitting member includes a wavelength selection film for selectively reflecting or transmitting each beam light according to its wavelength.